A great variety of lasers is presently known. The following summary includes those lasers most relevant to the laser of the present invention.
An RF matched CO.sub.2 waveguide laser is described in an article entitled "Parameters affecting the performance of a rf excited CO.sub.2 waveguide laser" in J. Appl. Phys. Vol. 56(9) 1 Nov., 1984 at pages 2497-2501.
Annular AC excited CO.sub.2 lasers are described in an article entitled "Electric discharge chamber for coaxial CO.sub.2 lasers" in Sov. J. Quantum Electron. (English Version) American Institute of Physics, Vol 14(5), May, 1984, pp. 647-649. An annular RF laser employing a DC field is described in an article entitled "Carbon-Dioxide Laser With High Power per Unit Length" in Electronics Letters Vol 5(4), Feb. 20, 1969, pages 63 and 64.
U.S. Pat. No. 3,748,594 describes a radio frequency electrically excited flowing gas laser wherein the discharge circuit is capacitively ballasted by providing capacitive impedance between the electrode and the gas. An RF excited annular laser having a relatively large gap is described in an article entitled: "Multipass Coaxial Radio Frequency Discharge CO.sub.2 Laser" in Optics Communications Vol. 58(6) 15 July, 1986, pages 420-422.
A 15 KW coaxial electrical discharge laser is mentioned in an abstract of AD Rep. 1976 U.S. NTIS Document AD-A030724.